Abstract: This invention relates to a process for recovering raw materials from a stream of residual or collected material (R) which comprises a plurality of different materials and which arises during the manufacture of paper (P) in a paper mill (1) and/or in a material processing installation (2) and/or in a paper machine (3) and which is discharged therefrom, wherein the stream of residual or collected material (R) is fed to an installation (4) for separating at least one fiber fraction contained in the stream of residual or collected material (R) via a screening operation and for separating an ash fraction (A) comprising black particles.

Abstract: The invention relates to a process for the production of paper on a paper machine containing a dilution headbox in which a main aqueous flow containing cellulosic fibres and filler is mixed in said headbox with a diluting aqueous flow to form a resulting aqueous flow which is ejected onto a wire and dewatered to form a web of paper, wherein one or more components providing improved retention are introduced into the main aqueous flow and an additive resulting in slower dewatering and/or being selected from non-ionic and anionic organic polymers is introduced into the diluting aqueous flow.

Abstract: A papermaking process with maintained retention and improved formation is provided. The papermaking process includes the step of adding bentonite to the white water prior to the exposure of the white water to the shear stages of the papermaking system. The bentonite may be added anywhere from the white water silo up to the introduction of the white water to the fan pump. The flocculant may also be added to the white water with or shortly after the addition of the bentonite or a split feed of flocculant may be provided whereby some of the flocculant is added to the white water and an additional portion of flocculant is added to the thin stock prior to the entry of the thin stock into the header box.

Abstract: Paper is produced by draining a paper stock containing process chemicals on a paper machine, a main stream of the paper stock and a dilution stream which consists of white water, contains at least 5% by weight of the process chemicals and amounts to 5-35% by volume of the total head box feed being fed via a head box to the paper machine wire. The papers thus produced have an excellent formation profile and an outstanding ash distribution.

Abstract: A method of papermaking having zero liquid discharge. A pulp slurry is produced from recycled cellulosic material and the slurry contains suspended cellulosic fiber material, solid contaminants and dissolved water soluble solids. The pulp slurry is subjected to a cleaning operation to produce a first flow stream containing the cellulosic fiber material and dissolved solids and a second flow stream containing dissolved solids along with solid contaminants. The first flow stream is washed with water to remove a substantial portion of the dissolved solids and provide a washed pulp which is used in a papermaking machine to produce a paper sheet. The second flow stream from the cleaning operation is compacted to produce a solid residue that can be landfilled and a liquid residue containing dissolved solids that can be recycled to the pulp cleaning operation.

Abstract: A paper-making machine includes a wet end associated with a wet fiber web, a headbox having an outlet gap, and a forming fabric positioned adjacent to the outlet gap and moving in a direction of web travel. An air/water separator is positioned in association with the forming fabric and downstream from the headbox relative to the direction of web travel. The air/water separator is configured for receiving liquid from the fiber web. A blower having a housing and an impeller is fluidly connected with the air/water separator. The impeller is rotatably carried by and within the housing and has a rotating hub with a periphery. The impeller also has a plurality of vanes attached to and extending from the hub and substantially equally spaced around the periphery. The vanes are formed of a non-metallic, composite material and have a coating of a layer of hydrophobic material substantially covering the composite material.

Abstract: The invention comprises a method for clarifying ink-laden water obtained from the recycling of paper stocks by treating said water with a hydrophilic dispersion polymer. The hydrophilic dispersion polymer of the invention is a copolymer of a diallyl N,N-disubstituted ammonium halide cationic monomer and (meth)acrylamide (AcAm). Following dosing with the polymer, a floc is formed. The floc contains ink and impurities which are removed from the water process stream by means of solid liquid separation; the solid liquid separation comprising a dissolved air flotation method. A preferred copolymer is formed from DADMAC and AcAm.

Abstract: Permanent wet strength agents are applied to the surface of the Yankee dryer along with the creping adhesive formulation and thereafter transferred to the tissue web as the tissue web is being adhered to the Yankee. When a sufficient amount of permanent wet strength agent is applied, improved temporary wet strength is attained.

Abstract: A method for arranging water circulation in a paper mill including a pulp manufacturing plant provided with a water circulation system, such as a TMP plant, and a paper machine provided with a water circulation system. In order to reduce the amount of fresh water supplied to the paper mill, a part of the amount of fresh water supplied to the paper mill is substituted for by water or waters cleaned locally from waters contaminated at the paper mill. The concentrate or concentrates obtained from the stages of water cleaning is/are utilized where applicable by arranging the concentrate(s) to flow upstream in relation to the raw-material flow for reuse at the paper mill. By means of these operations, the amount of contaminants circulating in the paper mill is controlled.

Abstract: A heat exchanger cools a process liquid in a paper-making machine using a source of cooling water. A first tank includes a plurality of first walls. A first inlet is connected to at least one of the first walls and the source and receives the cooling water from the source. A first outlet is connected to at least one of the first walls and the source. The cooling water is transported from the first outlet to the source. A second tank includes a plurality of second walls. The second tank has a second inlet connected with and receiving the process liquid from the paper-making machine, and a second outlet connected with and transporting the process liquid to the paper-making machine. An intermediate chamber is defined by and disposed between at least one of the first walls of the first tank and at least one of the second walls of the second tank. The intermediate chamber has a heat transfer liquid therein for transferring heat from the process liquid to the cooling water.

Abstract: A wet part of a paper making machine includes a distributor to which a main stream of a stock suspension is fed and which has a number of connections. The connections are connected by means of split stream lines to a machine-wide flow box which has a machine-wide slice nozzle (headbox). The split stream lines are connected (directly or indirectly) to the flow box. The slice nozzle is connected to at least one continuous web-forming screen. At least one collection trough is connected to the screen, as well as, optionally, to a backwater tank to accept the backwater trapped by the collection trough. Dilution water lines are provided to introduce backwater into the split stream lines to adjust the stock density of the split streams. The dilution water lines are connected directly to the collection trough.

Abstract: A process for manufacturing paper and paperboard that includes the steps of preflocculating granular starch with an aqueous solution containing cellulosic fibers and a flocculant prior to the introduction of the preflocculated mixture to either the white water, thick stock or thin stock. By preflocculating the starch in the presence of cellulosic fibers, improved formation is provided without compromising retention of the starch in the formed mat and distribution of the starch in the Z-direction is improved which improves the strength properties of the paper and paperboard.

Abstract: A method of determining the filler content of paper, wherein the paper stock is examined prior to delivering the stock to the de-watering section of the paper machine, and wherein the volume concentration of particles in the stock that have a size which is greater than the characteristic size of the filler is determined at varying mechanical working of the pulp, and the amount of filler retained in the paper is predicted from the result of at least two such determinations.

Abstract: In a foam laid process for producing a non-woven web of fibrous material (such as of synthetic or cellulose fibers) substantially fiber free foam is introduced at various locations in or adjacent to a headbox to get improved results. By introducing pure foam into the foam-fiber mixture near (e.g. just before) where the foam-fiber mixture is introduced into the headbox a more uniform basis weight profile of the non-woven web produced may be provided (e.g. a basis weight variation of about 0.5% or less). By introducing another stream of substantially fiber free foam into the headbox at a surface remote from the foraminous element, to flow along the surface (typically parallel to the flow of the foam fiber mixture), it is possible to minimize shear of fibers in the headbox so that the fibers do not become unidirectional, in the direction of movement of the foraminous element, and keep the surface clean. The surface is typically a roof surface of an inclined headbox.

Abstract: A process is disclosed which utilizes the "non-papermaking" portion of waste paper to produce a highly absorbent, essentially fiber-free granule which can be used, for example, as an agricultural chemical carrier. The process maximizes the amount of long (papermaking) fiber sent to the paper machine. The waste paper is broken up in a hydropulper, and the pulp stock is screened so that papermaking fibers are retained and sent forward to the papermaking process, and the solid material in the reject stream, such as kaolin clay and inorganic materials pass through a flotation clarifier to separate the solids. The slurry is then dewatered by means of a belt press to form a filter cake. The filter cake then enters a pin mixer where it is broken up into individual granules. The granules are then dried to a solids content of greater than 95%.

Abstract: Procedure for the drainage of the wire and/or press section of a paper machine, in which procedure at least one suction pipe (1) is provided with at least one gap (2) and the suction pipe (1) is connected to a vacuum device (4) to develop a vacuum at least in this vacuum pipe, and in which procedure a felt, wire or equivalent (3) is moved over the gap of the suction pipe, water being thus drained from the felt, wire or equivalent. In the procedure, the vacuum capacity is adjusted by measuring and/or adjusting at least the amount of water drained from the suction pipe (1) and, on the basis of the measured data, adjusting the vacuum capacity by means of regulating devices (11, 12). The invention also relates to an apparatus for adjusting the vacuum capacity.

Abstract: Enzymatic dehalogenation of undesirable nitrogen-free organohalogen compounds is carried out by adding a dehalogenase to an aqueous composition comprising a nitrogen-free organohalogen compound and a nitrogen-containing cationic polymer. The enzymatic dehalogenation of the nitrogen-free organohalogen compound is achieved without any substantial effect upon the nitrogen-free organohalogen compound. The dehalogenation method may be carried out via continuous, batch, or semi-continuous processes.

Abstract: A process and apparatus for pumping a fluid mixture of a gas and a liquid and for separating said gas and liquid from each other, said apparatus having a fluid inlet (14) at one end (18) and at the opposite end (22) a pump housing (16) with a liquid outlet (28) and, between said inlet (14) and said pump housing (16), a hollow elongated gas separation part (30) of an essentially circular cross section with a generally central outlet (26) for separated gas. Said gas separation part (30) is provided by a hollow rotor (12) between said inlet (14) and said pump housing (16), the inner wall of said rotor (12) providing a large rotatable gas separation surface (32). The diameter of said rotor (12) increases at said opposite end (22) of the apparatus to form a larger diameter pumping zone (17) extending into said pump housing (16). Said rotor (12) is provided with a blade wheel (24) extending into said pump housing (16).

Abstract: Method of producing a nonwoven material by hydroentangling of a fiber web, whereby dry fibers, natural and/or synthetic, are metered into a dispersion vessel, possibly after pre-wetting. The fibers are dispersed in a foamable liquid including water and a tenside for forming a foamed fiber dispersion, which is applied to a wire and drained. The formed fiber web is subjected to hydroentangling directly after forming and the foamable liquid, after having passed through the wire, is recirculated to the dispersion vessel in a simple closed circuit.

Abstract: A process for the production of paper by mixing an aqueous phase comprising white water with cellulose containing fibres, and optional fillers, in a mixing stage to form an aqueous suspension, draining the suspension in the presence of a drainage or retention aid to form a fibre containing sheet or web and white water, and recirculating at least part of the white water to the mixing stage, whereby at least part of the white water is subject to electrodialysis before the mixing stage.

Abstract: A method of papermaking having zero liquid discharge. A cellulosic pulp composed of recycled materials is initially cleaned to remove contaminants and foreign material, and the clean pulp is then washed to remove dissolved solids and pulping chemicals, and the washed pulp is then utilized in the papermaking process. The contaminants are separated from the liquid residue resulting from the pulp cleaning operation, preferably by floatation clarification, and the effluent from the clarification is evaporated to produce steam or water vapor along with an evaporated residue. The evaporated residue is combined with the suspended solids that were removed from the liquid residue and the combined residue is then subjected to a mechanical dewatering operation to reduce the water content so that the dewatered material can then be either landfilled or incinerated. The condensate from the evaporation can be combined with fresh makeup water and used in the papermaking process.

Abstract: In a method of recovering fibers from white water using a filter including a vat and a rotating filter surface (such as a disc filter), auxiliary pulp is supplied to the area of the vat where the cleaned and rotating filter surface meets the pulp surface in the vat. The consistency difference in the filter vat is adjusted by controlling the auxiliary pulp flow, or by adding cloudy filtrate to the auxiliary pulp prior to the filter vat. The auxiliary pulp is preferably supplied to the filter by using directing nozzles or other supply structures, and essentially evenly over the entire radial width of the filter surface.

Abstract: There is disclosed a process for separating fine solids from water in the used water recovery system of a sheet forming mill, wherein the used water recovery system includes at least one stage in which an alkaline earth metal carbonate is precipitated in the aqueous suspension constituting the used water whereby the particulate material present in the used water becomes entrained in the alkaline earth metal carbonate precipitate. By the invention it is possible to recover the water and the fine solid materials which pass through the wire mesh belt of a paper or board forming machine, and optionally recycle those recovered materials.

Abstract: Method of producing a foam-formed fibre or paper web, whereby a foamed fibre dispersion is formed by dispersing natural and/or synthetic fibres in a foamable liquid comprising water and a tenside in a dispersion vessel (111) and by conveying the foamed fibre dispersion to a wire (118) on a paper machine. The foamed liquid which is removed through the wire (118) is conveyed to a closed foam tank (128) in which a draining of the liquid to the bottom of the tank occurs, whilst the lighter foam is collected in the top of the foam tank. Liquid from the bottom of the foam tank is led to the dispersion vessel (111) via a first pipeline (129), whilst foam passes to the dispersion vessel via a second pipeline (130) in the top of the foam tank where the fibres are added and dispersed in the foamable liquid.

Abstract: This invention relates to recently developed systems which produced bleached recycled fibers from high lignin content recovered paper materials such as old corrugated containers and old newspapers. Such systems of this type, generally, use chemical digestion (e.g., the kraft process) to reduce the lignin content prior to bleaching. Since recovered paper materials normally have high levels of aluminum, which are derived from the paper sizing and pH control chemical, aluminum sulfate; and since soluble aluminum causes scaling of evaporators in the kraft digestion-chemical recovery cycle, there is a need for a means to remove soluble aluminum from the recovered paper materials prior to digestion.

Abstract: A method for improving the quality of multilayer and multiply papers in the wet section of a paper machine, wherein at least two stock suspensions of different quality are used for producing a paper web. The wire water removed through the paper machine wire is collected in separate vessels and recycled. At least the major part of a first stock suspension is dewatered through a first wire, while at least the major part of a second stock suspension is dewatered through a second wire. The wire water removed through each of the wires is collected, separately from the other wire water, and recycled to the stock suspension of the same layer.

Abstract: A paper machine forming section with two wire forming units. One of the two forming units is a twin wire web forming unit having a headbox, two wire loops arranged in sandwich-like manner and a drainage element for each of the wire loops. The first web-forming unit has a first section including a curved suction drainage element or roll in the first lower wire loop; a second section with opposing drainage ledges, wherein the drainage ledges are stationary on the upper side and the drainage ledges are developed resiliently pressable on the bottom side; the drainage ledges of the upper and lower sides are arranged staggered with respect to each other in the direction of travel of the wire, and at least the ledges of the upper side are developed with suction; a third section which has at least one suction wire separating element on one side. The second web-forming unit is a hybrid former with a single wire.

Abstract: In a process for making a particulate or granular material from a reject stream from a coated grade waste paper pulp stock recycling process, fibers for use in making paper are removed, the remaining solid material in the reject stream is dyed and then separated. Water is removed from the reject stream to increase its consistency and form dyed particles or granules. The process and characteristics of particulate and granular material formed by the process are described.

Abstract: The invention relates to a method for reducing the amount of interference substances in the water circulations of processes involving wood-based fibre suspensions by binding the disturbance substances to the fibres by means of cationic starch. The amount of the said starch added to the fibre suspension is approximately 0.04-0.5% of the fibre weight.

Abstract: To regulate the basis weight cross section of the fiber suspension dispensed by the outlet of a headbox of a paper making machine onto the screen or screens of the following forming section, the headbox is sectioned across the width of the machine with individual first sections of fiber suspension across the width. The fiber suspension on the screen(s) in the following forming section is drained and the drained filtrate is collected in second sections respectively generally corresponding to the first sections of the headbox. The removed sectioned filtrate is recycled to the respective sections of the headbox and is mixed with the suspension normally entering the headbox to regulate and make more uniform the basis weight cross section of the fiber suspension.

Abstract: The invention relates to a process and an apparatus for recycling backwater in a papermaking machine. According to the invention backwater draining through a forming fabric is collected into several collecting means (51, 52, 53, 54) and pumped by separate pumps (20) in at least two and preferably numerous separate flows (81 to 85) directly as substantially air free separate flows to the fibre process (12, 30, 40) of the short circulation in order to implement a fast, air free and split recycling of backwater from said forming fabric to said fibre process.

Abstract: There is disclosed a process for separating fine solids from water in the used water recovery system of a sheet forming mill, wherein the used water recovery system includes at least one stage in which an alkaline earth metal carbonate is precipitated in the aqueous suspension constituting the used water whereby the particulate material present in the used water becomes entrained in the alkaline earth metal carbonate precipitate. By the invention it is possible to recover the water and the fine solid materials which pass through the wire mesh belt of a paper or board forming machine, and optionally recycle those recovered materials.

Abstract: A pulp furnish containing predominantly wood-containing fibers (mechanical) and natural calcium carbonate as a filler is formed into a paper in a paper forming section of a paper machine at a neutral pH in the range of 6.7 to 7.5. Bentonite plus a suitable polymer such as a polyacrylamide produces a pulp stock that has exceptionally high drainage characteristics particularly when used with chalk as the filler. The pH of the stock in the headbox is maintained at the desired level of pH 6.7-7.3 by monitoring the pH in the headbox and adjusting the flow of pH reducing and buffering agent, preferably phosphoric acid, into the pulp prior to the headbox to obtain the desired pH in the stock.

Abstract: Waste lignocellulosic material, for example brown kraft grocery bag and corrugated paperboard, is treated in a multi-step process to produce a recycle brownstock pulp having a sufficiently low kappa number that it may be bleached according to conventional means such that its final optical and strength properties are comparable to that of virgin pulps bleached according to similar means; biological enzymes are used in conjunction with medium consistency pulping to separate fibers and loosen contaminants, such as wax and adhesives; low temperature soaking of waste lignocellulosic material in an alkaline peroxide liquid using long reaction times is used to minimize energy consumption, degrade contaminants, and to selectively remove lignin; loosened contaminants and poorly bonding lignocellulose debris are removed by screening and cleaning methods; high consistency peroxygen cooking is used to substantially delignify the pulp and to destroy contaminants in an energy efficient manner; liquid streams are treated an

Abstract: The present invention relates to a method of making paper from bleached or alkaline treated pulp by dewatering pulp containing bleached or alkaline treated vegetable fibers from wood or non-wood species. It was found that such bleached or alkaline treated pulps contain a substantial amount of harmful pectins. By incorporating pectinase in the bleached or alkaline treated pulp such harmful pectins in the aqueous phase of the pulp are degraded and thus rendered harmless to papermaking processes.

Abstract: Liquid process streams--such as white water, pressate, or washer filtrate from a pulp and paper mill--are clarified in an efficient manner using a gas sparged hydrocyclone, which takes up a minimum of floor space. A liquid stream having a consistency of less than about 0.5% solids is introduced into a first end of a vortex. Gas is sparged into the liquid in the vortex to cause particles to attach to gas bubbles and move through a rejects outlet at the first end of the vortex, while clarified liquid is removed from a second end of the vortex. A pedestal is typically provided at the accepts outlet, having a radial clearance with the inside of a porous tube through which the gas is sparged that is about 8-12% the radius of the porous tube.

Abstract: White water from a paper machine is treated in an improved fiber recovery process, i.e., the "save-all" process. Prior to the mixing of sweetener stock into the white water the sweetener stock is fractionated (undiluted) into fine and coarse fiber fractions, of which only the coarse fraction is fed as sweetener stock into the white water. The inlet line for the sweetener stock is provided with a fractionation apparatus for removing the fine fraction from the sweetener stock. Treatment apparatus may also be utilized to separate the white water into fine and coarse fractions before passing the fine fraction to a mixer for mixing with the sweetener stock coarse fraction.

Abstract: Polyglycerol esters have been found to be effective antifoam agents in aqueous systems employed in paper processing. Adjunct antifoam agents are not required. Best results are obtained with polyglycerol esters having a degree of glycerine polymerization in the range of 3 to 6 and an esterification range of 15 to 85%.

Abstract: A papermaking water system utilizing vacuum pump sealing water and having a zero sealing water discharge. A group of water seal vacuum pumps are used in a papermaking machine to generate subatmospheric pressure in suction equipment and thereby extract water from a wet paper web. During operation of the vacuum pumps, the sealing water is heated and the heated water is discharged to a cooling tower to cool the water which is then recirculated to the vacuum pumps. Steam from a generating plant is supplied to the dryer drums in the dryer section of the papermaking machine, and the steam condensate is combined with the heated sealing water flowing to the cooling tower. By using steam condensate as makeup water, no ionic buildup will occur in the closed system, and high quality water is withdrawn from the closed system and may be used in other sections of the papermaking machine, so that there is no discharge of sealing water to the sewer system.

Abstract: This invention relates to a method for the recovery of organic substances dissolved or brought into a colloid form during the manufacture of a mechanical pulp where said mechanical pulp has not been subject to previous alkaline bleaching or other previous process carried out under alkaline conditions. The method is characterized in the deacetylation of the galactoglucomannans having been brought into dissolved or colloidal form during the pulping process, and subsequent deposition of said deacetylated glucomannans onto a solid phase, such as pulp fibers or organic or inorganic additives. The deacetylation is performed either by alkali or enzymatically. The method diminishes the organic substance loading on recycling waters and effluents, and improves the yield and strength properties of the pulp.

Abstract: A method for clarifying the laser print deinking loop water in a papermaking process by using a water soluble graft copolymer having the structure: ##STR1## wherein E is the repeat unit obtained after polymerization of an .alpha.,.beta. ethylenically unsaturated compound, the molar percentage of a:b is from about 95:5 to 5:95, with the proviso that the sum of a and b equals 100%; G comprises the structure: ##STR2## wherein d is a cationic monomer, R.sub.1, R.sub.2 and R.sub.3 are the same or different and are hydrogen or a lower alkyl group having C.sub.1 to C.sub.3, F is the salt of an ammonium cation and the molar percentage of c:d is from 95:5 to 5:95 with the proviso that the sum of c and d equals 100%.

Abstract: White water from a paper machine is treated in an improved fiber recovery process, i.e., the "save-all" process. Prior to the mixing of sweetener stock into the white water the sweetener stock is fractionated (undiluted) into fine and coarse fiber fractions, of which only the coarse fraction is fed as sweetener stock into the white water. The inlet line for the sweetener stock is provided with a fractionation apparatus for removing the fine fraction from the sweetener stock. Treatment apparatus may also be utilized to separate the white water into fine and coarse fractions before passing the fine fraction to a mixer for mixing with the sweetener stock coarse fraction.

Abstract: Method of feeding separate streams of (1) an aqueous dispersion of pulp and (2) white water from a paper making process into a wedge-shaped space between horizontal travelling upper and lower converging wire meshes, applying a siphon means to the upper wire mesh in said zone to form a web of solid fibrous material between the meshes separating the upper wire mesh from the web to leave it supported on the lower wire mesh as the meshes leave the wedge-spaced zone; washing all solids from the wire meshes into a receiving vessel, recycling the contents of the receiving vessel to the paper making process, and recycling the liquid from the white water to the paper making process; and apparatus to perform the above method.

Abstract: A method for oxidizing organic and/or heavy metal contaminants in wastewaters, sludges, or soils containing such contaminants by contacting the wastewaters, sludges, or soils with soybean peroxidase and a peroxide.

Abstract: A process for the production of papermaking fiber or pulp from waste solids emanating from pulp and paper mills, particularly waste solids in process water streams containing fibrous solids that cannot be directly recycled by paper mill "saveall" devices, from pulp and paper mill process water streams conveyed by the sewerage system to wastewater treatment plant facilities, and from "sludge" emanating from the underflow of a primary clarifier or sedimentation basin at pulp and paper mill wastewater treatment facilities either before or after the "sludge" is thickened and dewatered.

Abstract: A process for the production of papermaking fiber or pulp from waste solids emanating from pulp and paper mills, particularly waste solids in process water streams containing fibrous solids that cannot be directly recycled by paper mill "saveall" devices, from pulp and paper mill process water streams conveyed by the sewerage system to wastewater treatment plant facilities, and from "sludge" emanating from the underflow of a primary clarifier or sedimentation basin at pulp and paper mill wastewater treatment facilities either before or after the "sludge" is thickened and dewatered.

Abstract: Method and apparatus for reducing contamination in processed pulp and in white water effluent discharged from a pulp dryer or paper making mill. The system includes multiple pulp bleaching and washing stages wherein white water effluent discharge from the dryer or paper making mill is fed to the next-to-last washing stage and fresh water is supplied to the last washing stage.

Abstract: A layer of particulate material is formed by forming a foamed dispersion of a particulate material, supplying the foamed dispersion to a predetermined zone of a plane through which a foraminous element is moving, applying a vacuum to said plane across the zone on the other side of the foraminous element, so as to drain foam and form a particulate layer thereon, removing any free air from the drained foam, and continuously recycling the resulting foam for re-use in forming the foamed particulate dispersion. An apparatus is provided for carrying out the process.

Abstract: Apparatus for treating of old printed papers includes a recycling conduit for the thickening waters of a long fiber fraction upstream of the fractionation apparatus to the pulping and pre-purification apparatus, and a reservoir for the recovery of thickening waters of a short fiber fraction and of thickening/washing waters of the long fiber fraction. This reservoir is fed with clean water for starting the installation and is connected with a second reservoir such that overflow from the first reservoir empties into the second reservoir.

Abstract: This device, preferably formed as a dual paper machine, has according to a preferred embodiment two endless screens, mainly a lower screen (21) and an upper screen (22). The lower screen (21), on which is formed a paper web, and the upper screen (22) are moved together in the lower part of a dehydration cylinder (25) arranged in the upper screen. Both screens (21,22) are unrolled from the rising lower quadrant of said cylinder (25) and are laid on the upper part of the support cylinder (26) arranged in the lower screen (21). The bandage of the dehydration cylinder (25) has hollows which absorb water from the screens along their arcs of contact with the cylinder and which project the water towards the inside of the loop formed by the screens of the cylinder. In the feed direction of the screens and downstream of the support cylinder (26), there is arranged a receiving container (36) for the projected water.